The preparation and serving of large numbers of meals in an institutional setting has long posed a variety of problems. The ability to serve palatable meals with the various dishes being served at optimum temperature often conflicts with efforts to make service of the meals easier, more efficient and less manpower intensive.
The preparation, storage, rethermalization and service of a large number of meals has evolved through several stages. Initially, trays were filled with food from various hot or cold storage containers just prior to serving, and then transported to the individual serving areas, such as patient's rooms in a hospital. However, as facilities grew larger, the assembly of trays from a centralized area became very difficult if not impossible. Frequently in such a system, the time between tray assembly and service grew longer, which resulted in food spoiling or being served at an unpalatable temperature.
One solution has been a food service system of trays and carts using heating elements inside of a refrigerator. In this type of system, trays are pre-assembled and loaded into the carts. In the refrigerator, the food remains cold. At a desired time, the heating elements are activated to rethermalize and maintain some of the food in a heated condition, while not effecting the rest of the food which is to remain cold. After the food has reached the serving temperatures the carts are rolled to the service locations and the trays served.
However, even these systems have problems. Such systems rarely provide significant operator feedback relating to whether the carts are properly connected in the refrigerators and the overall functioning of the system. Even those systems that check for a voltage on the lines providing power to the heaters cannot determine if the drop is due to an open circuit or the resistance of the heater element.